Of the more than 2,000 people asked, 11 per cent said they still don’t know which way they will vote at the EU referendum on June 23.

But when undecideds are removed from the poll results, Brexit is favoured by 51 per cent to 49 per cent wanting the UK to remain in the EU.

Jennifer Bottomley, from ICM, said: “With six weeks left until polling day, this week marks the fifth consecutive poll in our weekly series to put the Leave side slightly ahead, with a 51per cent vs 49 per cent split on the referendum question.

“However, it’s worth noting that a large part of this reflects our introduction of turnout weighting at the beginning of April – which suggests that those campaigning to Remain need to focus not only on the debate itself, but also on ensuring that their supporters actually come out to vote on referendum day.”